1. Field of the Invention
This invention relates to a new and improved bottle cap used to close containers of the type used on water dispensers and water coolers. More particularly, the cap has tamper-evident features and, more specifically, is constructed so that it may be applied to conventional containers (e.g., 5-gallon water bottles) using conventional capping equipment. The cap is formed with an open-ended well in the center which is initially closed by a slidable plug. The invention further comprises the use of such a cap with a dispenser system having a dispenser tube which fits into the well, engages the plug and pushes the plug away from the well. When the container is empty or nearly empty, as the container is removed from the dispenser, the tube pulls the plug back into its initial position, preventing any liquid remaining in the container from spilling.
2. Description of Related Art
U.S. Pat. No. Re. 32,354 discloses use of a flexible bag contained within a box fitted with an adapter which seals around an opening in the bag and is secured to an opening in the box. A tubular spigot probe is inserted into the adapter to engage a movable plug within a sleeve which is a permanent part of the adapter. As the probe is inserted into the sleeve, it seals thereagainst and also fastens itself to the plug. Continued insertion of the probe pushes the plug inwardly of the bag. When the probe is withdrawn, the plug is pulled back into the sleeve. The present invention constitutes an improvement over U.S. Pat. No. Re. 32,354 in that the adapter of that patent is considerably modified so that the present invention embodies a modification of a conventional bottle cap adapted to snap onto a conventional, large bottle for liquids such as water bottles. The box of U.S. Pat. No. Re. 32,354 in which the bag is contained is entirely eliminated in accordance with the present invention. In one embodiment of the present invention, applicant's plug is formed with external longitudinal grooves and notches in the bottom edge of the plug aligned with the grooves making the skirt flexible and facilitating re-entry of the plug into the sleeve. The grooves and notches facilitate ejection of the plug from the mold in which it is fabricated. The grooves further initiate communication between the container and the exterior earlier than would otherwise be the case.
U.S. Pat. No. 4,699,188 shows a water dispensing system using a conventional large liquid container closed with a snap-on type cap having a well formed therein initially closed with a frangible bottom. The dispenser has a tube formed with a point which penetrates the bottom of the cap well and permits discharge of liquids through the dispenser tube. A disadvantage of the structure of this patent is that there is no means for reclosing the bottom of the well. Hence, when the container is removed, if any liquid remains therein it leaks through the pierced bottom of the capped well.
PCT Publication WO90/0399 discloses an improvement upon U.S. Pat. No. 4,699,188. U.S. Pat. No. 5,121,778 is an improvement upon the PCT Publication. In these structures, the bottom of the cap well is initially closed by a plug integrally formed with the well. When the container is installed in a dispenser, a tube of the dispenser fits into the well and engages the plug. Continued movement of the container causes the dispenser tube to break the connection between the plug and the well and pushes the tube into the container, allowing liquid to be dispensed through the tube. When the container is removed from the dispenser, the tube pulls the plug back into the well and then disengages therefrom, whereby the plug prevents leakage of the liquid. The present invention comprises an improvement on the above reference in that the plug is not formed initially as part of the well, but is a separate member inserted therein. Thus the present invention provides improved dimensional control for the plug engaging the dispenser tube and being disengaged therefrom when the plug is reinserted in the well. Further, the interfitting sealing surfaces of the well and plug of the present invention are seamless and, therefore, smooth. One embodiment of the present invention uses longitudinal grooves on the exterior of the plug skirt below the seamless circumferential bead on the skirt which seals against the seamless interior of the well. Hence the seal of the plug is broken as soon as the plug moves a short distance relative to the well, an event which occurs before the probe or dispenser tube locks on the plug.